Area forecast discussion
National Weather Service Gray ME
705 PM EDT Sat may 25 2013
Synopsis...
low pressure will move slowly through the Gulf of Maine overnight
and Sunday, then into the Maritimes Sunday night. High pressure will
build in from the west Monday then shift offshore on Tuesday. A warm
front will move across the region Wednesday and Wednesday night
followed by a large building ridge of high pressure with very warm
temperatures for late in the week.
&&
Near term /until 7 am Sunday morning/...
655 PM...adjusted 1st period grids based largely on mesonet for
this estf update. The snow levels were lowered to near 2000 thousand feet
across the northern White Mountains for this update. Tide at
Portland Harbor continues to run near 0.4 feet above projected.
Regarding river flooding...
Androscoggin at Gorham New Hampshire
Connecticut at Dalton
Kennebec at Skowhegan
Are now expected to exceed flood stage. Additional forecast points are
being monitored as well for flooding potential.
Previous disc... slow moving low moving
NE through the Gulf of ME tonight will continue rain across the forecast area.
However...as colder air moves in and the freezing level drops with
the cutoff strengthening and drifting overhead the rain will mix
with or change to snow with some ice pellets/freezing rain possible as well across the
higher elevations...mainly above 2000 feet. Some light snow accumulation
possible with 1 to 4 inches possible above 4000 feet.
Gusty northerly winds will ease up only a little overnight as
temperatures only drop a few degrees with cloud cover and prcp. Look for
lows in the 30s north and upper 30s to Lower/Middle 40s S.
Generally used a blend of NAM/GFS and met/mav guidance for the
near term forecast.
Flood Watch now for all of the western ME Montana and foothill zones and
northern New Hampshire. See the hydrology discussion below for more details.
&&
Short term /7 am Sunday morning through Sunday night/...
the surface low continues to move slowly NE Sunday then accelerates
into the Maritimes Sunday night. Thus expect the rain /or mixed prcp
at higher elevations above 2000 feet/ to gradually end or at least
taper off on Sunday then come to an end Sunday night from SW to NE.
Some clearing likely late Sunday night especially SW zones.
Generally used a blend of GFS/NAM, met/mav and HPC/rfc quantitative precipitation forecast for the
short term forecast.
&&
Long term /Monday through Saturday/...
high pressure builds across the region for Monday and Tuesday before moving
offshore Tuesday night. A warm front will approach from the west Wednesday
and move through the area by later Wednesday night producing showers
ahead and along the warm front. On Thursday a large ridge of high
pressure that will build over the eastern third of the US will also build
north across New England for both Thursday and Friday bringing very
warm and humid conditions to the area.
Used a blend of the mav/met temperatures for 4th/5th periods. Used gmos for
maximum temperatures but had to raise temperatures some for Thu/Fri/Sat. For mins
use the bias adjacent mex guidance.
&&
Aviation /00z Sunday through Thursday/...
short term /through Sunday night/...mainly IFR/LIFR tonight with
conditions improving Sunday and Sunday night to VFR. Mixed prcp at
higher elevations developing tonight then ending Sunday/Sunday evening.
Long term...
VFR conds xcpt MVFR conds Wednesday/Wednesday night in any showers.
&&
Marine...
short term /tonight through Sunday night/...will extend the Small Craft Advisory
through 11 PM this evening for wind gusts and seas based on latest buoy
reports and slow track of surface low. Winds let up overnight but seas
will be slow to subside over the open waters. May need to extend
the Small Craft Advisory at least for hazardous seas over the open waters for late
tonight and possibly into Sunday as well.
Long term...no flags Monday or Tuesday...by Wednesday an increasing southerly flow
may allow Small Craft Advisory conds to develop.
&&
Fire weather...
fire weather danger very low. Excessive rainfall past several days and
more rain or even mixed prcp over the higher terrain through tonight and
only slowly letting up Sunday along with green up over much if not
all of the forecast area.
&&
Hydrology...
generally used a blend of GFS/HPC/rfc quantitative precipitation forecast. 24 hour quantitative precipitation forecast amounts
tonight through Sunday around 1/2 inch with some amounts topping 1 inch
possible across north/Montana foothill zones due to upslope enhancement with
low/middle level winds advecting moisture in off the Atlantic. Will
expand the Flood Watch to include Somerset County /thru 8 am
Sunday/ where a river Flood Warning is currently in effect for
the Kennebec at Skowhegan.
&&
Tides/coastal flooding...
the predicted high tide is 11.8 feet at 1158 PM tonight at pwm. Tidal
flood stage is 12.0 feet. There has been a surge of 1/4 to just
under 1/2 feet over the past couple days. Now that winds are from
the north that may be lowered a bit...but still could see the tide
reach the 12 feet benchmark for minimal coastal flooding. More
significant are the wave over the coastal waters...running 5 feet at
the pwm buoy. Wave action will create some splashover and beach
erosion. Will issue a coastal Flood Advisory for the high tide
around midnight tonight.
&&
Gyx watches/warnings/advisories...
ME...Flood Watch through Sunday morning for mez007>009-012>014.
Coastal Flood Advisory from 10 PM this evening to 2 am EDT
Sunday for mez023>028.
New Hampshire...Flood Watch through Sunday morning for nhz001>005.
Coastal Flood Advisory from 10 PM this evening to 2 am EDT
Sunday for nhz014.
Marine...Small Craft Advisory until 11 PM EDT this evening for
anz150>154.
&&
$$
Es
